The Binary Mode of Star Formation
Hans Zinnecker
Astrophys. Inst. Potsdam
Observations over the past decade have shown that most young stars are
born in binary or multiple systems. The binary mode of star formation
seems to be the rule rather than the exception. This has important
implications for our understanding of the Initial Mass Function,
the star formation history, and the formation of planetary systems,
some of which will be discussed in this talk.
After a brief historical introduction, we will review our current knowledge
about the binary nature of young stars (frequency as a function of mass,
distributions of mass ratios and separations, dependence on star formation
environment, proto-binary systems). Then we will demonstrate the astrophysical
potential of young binaries (e.g. deriving dynamical masses, testing
pre-Main Sequence tracks, constraining the fragmentation process).
We will also raise the subject how to synthesize the galactic field star
population mix using young vs. old binary statistics. Finally we will
take a look at the future of young binary star research, with a view to the
forthcoming facilities (Keck, VLT, and LBT interferometers, as well as ALMA
and SMA).